Irena Oblak

Irena Oblak


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 August 2011 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
VVVaneja Velenik
Vaneja Velenik
JOJanja Ocvirk
Janja Ocvirk
MMMaja Music
Maja Music
MBMatej Bracko
Matej Bracko
FAFranc Anderluh
Franc Anderluh
MOMirko Omejc
Mirko Omejc
Preoperative capecitabine-based chemoradiation is a standard treatment for locally advanced rectal cancer (LARC). Here, we explored the safety and efficacy of the addition of bevacizumab to capecitabine and concurrent radiotherapy for LARC.

2 August 2018 in Radiology and Oncology
Verified
Journal Article
Open access
PDF file
IRIvica Ratosa
Ivica Ratosa
AJAljasa Jenko
Aljasa Jenko
IOIrena Oblak
Irena Oblak
Background: Breast radiotherapy is an established adjuvant treatment after breast conserving surgery. One of the important individual factors affecting the final cosmetic outcome after radiation is breast size. The purpose of this review is to summarise the clinical toxicity profile of adjuvant radiotherapy in women with breasts of various sizes, and to evaluate the treatment planning studies comparing target coverage and dose to thoracic organs at risk in relation to breast size. Conclusions: Inhomogeneity and excessive radiation dose (hot spots) in the planning of target volume as well as large volume of the breast per se , all contribute to a higher rate of acute adverse events and suboptimal final cosmetic outcome in adjuvant breast cancer radiotherapy, regardless of the fractionation schedule. Improved homogeneity leads to a lower rate of ≥ grade 2 toxicity and can be achieved with three-dimensional conformal or modulated radiotherapy techniques. There may be an association between body habitus (higher body mass index, bigger breast size, pendulous breast, and large chest wall separation) and a higher mean dose to the ipsilateral lung and whole heart. A combination of the technical innovations ( i.e . the breath-hold technique, prone position with or without holding breath, lateral decubitus position, and thermoplastic bra), dose prescription ( i.e . moderate hypofractionation), and irradiated volume ( i.e . partial breast irradiation) should be tailored to every single patient in clinical practice to mitigate the risk of radiation adverse effects.

1 January 2012 in Radiology and Oncology
Verified
Journal Article
Open access
IOIrena Oblak
Irena Oblak
PPPrimoz Petric
Primoz Petric
FAFranc Anderluh
Franc Anderluh
VVVaneja Velenik
Vaneja Velenik
PFPeter Fras
Peter Fras
The aim of the retrospective study was to evaluate the effectiveness and toxicity of radiochemotherapy in patients with squamous cell carcinoma of the anal canal treated at a single institution. Between 1/2003 and 9/2010, 84 patients were treated with radical radiochemotherapy at the Institute of Oncology Ljubljana, Slovenia. The treatment consisted of 3-dimensional conformal external beam radiotherapy with concurrent chemotherapy (5-fluorouracil and mytomycin C), followed by brachytherapy or external beam boost. The toxicity of therapy and its effectiveness were assessed. The treatment was completed according to the protocol in 79.8% of patients. The median follow-up time of 55 survivors was 53 months (range: 16-105 months). The 5-year locoregional control (LRC), disease-free survival (DFS), disease-specific survival (DSS), overall survival (OS) and colostomy-free survival (CFS) rates were 71%, 68%, 81%, 67% and 85%, respectively. No treatment-related mortality was observed. The most frequent acute side-effect of the treatment was radiodermatitis (grade 3-4 in 58.2% of patients). LENT-SOMA grade 3-4 late radiation side effects were observed in 15 (18%) patients. In patients with brachytherapy boost a trend of less late side effects was observed compared to patients with external beam boost (P=0.066). On multivariate analysis, complete clinical disease response was identified as an independent prognostic factor for LRC, DFS and DSS, the salvage surgery for LRC and DFS, whereas Hb below 120 g/l retained its independent prognostic value for OS. Radiochemotherapy provides an excellent disease control and the survival with preserving anal sphincter function in majority of patients. Surgical salvage with abdominoperineal resection for persistent or recurrent disease has curative potential.

29 September 2010 in Radiation Oncology
Verified
Journal Article
Open access
PDF file
VVVaneja Velenik
Vaneja Velenik
IOIrena Oblak
Irena Oblak
FAFranc Anderluh
Franc Anderluh
This study evaluated the effectiveness and safety of preoperative chemoradiotherapy with capecitabine in patients with locally advanced resectable rectal cancer. This report summarizes the results of the phase II study together with long-term (5-year) follow-up.

16 February 2016 in Radiology and Oncology
Verified
Journal Article
Open access
PDF file
IOIrena Oblak
Irena Oblak
MCMonika Cesnjevar
Monika Cesnjevar
MAMitja Anzic
Mitja Anzic
JHJasna But Hadzic
Jasna But Hadzic
AEAjra Secerov Ermenc
Ajra Secerov Ermenc
PKPeter Korosec
Peter Korosec
Background: Radiochemotherapy is the main treatment for patients with squamous cell carcinoma of the anal canal. Anaemia is reported to have adverse effect on survival in cancer patients. The aim of the study was to evaluate the influence of anaemia on radiochemotherapy treatment outcome in patients with squamous cell carcinoma of the anal canal. Patients and methods: One hundred consecutive patients with histologically confirmed squamous cell carcinoma of the anal canal were treated radically with 3-dimensional conformal or intensity-modulated radiation therapy followed by brachytherapy or external beam radiotherapy boost and with concurrent mitomycin C and 5-fluorouracil. The influence on survival of pre-treatment, mean on-treatment and end-of-treatment haemoglobin (Hb) concentrations was studied. Results: The 5-year locoregional control, disease free survival, disease specific survival and overall survival rates for all patients were 72%, 71%, 77% and 62%, respectively. In univariate analysis, patients with pre-treatment and end-of-treatment Hb > 120 g/L survived statistically significantly better compared to patients with Hb ≤ 120 g/L. Patients with mean on-treatment Hb > 120 g/L only had statistically significant better locoregional control and overall survival than patients with Hb ≤ 120 g/L. In multivariate analysis, independent prognostic factors were pre-treatment Hb (> 120 g/L vs. ≤ 120 g/L) for overall survival (hazard ratio [HR] = 0.419, 95% confidence interval [CI] = 0.190–0.927, p = 0.032) and stage (I & II vs. III) for disease specific (HR = 3.523, 95% CI = 1.375–9.026, p = 0.009) and overall survival (HR = 2.230, 95% CI = 1.167–4.264, p = 0.015). Conclusions: The pre-treatment, mean on-treatment and end-of-treatment Hb concentration > 120 g/L carried better prognosis for patients for with squamous cell carcinoma of the anal canal treated with radiochemotherapy. The pre-treatment Hb > 120 g/L was an independent prognostic factor for overall survival of patients with anal canal cancer.

1 June 2013 in Radiology and Oncology
Verified
Journal Article
Open access
IOIrena Oblak
Irena Oblak
VVVaneja Velenik
Vaneja Velenik
FAFranc Anderluh
Franc Anderluh
BMBarbara Mozina
Barbara Mozina
JOJanja Ocvirk
Janja Ocvirk
Background. The aim of this study was to analyse whether the level of tissue inhibitor of metalloproteinases (TIMP) 1 is associated with the tumour response and survival to preoperative radiochemotherapy in rectal cancer patients. Patients and methods. Ninety-two patients with histologically confirmed non-metastatic rectal cancer of clinical stage I- III were treated with preoperative radiochemotherapy, surgery and postoperative chemotherapy. Plasma TIMP-1 concentrations were measured prior to the start of the treatment with an enzyme-linked immunosorbent assay (ELISA). Results. Median follow-up time was 68 months (range: 3-93 months) while in survivors it was 80 months (range: 68-93 months). The 5-year locoregional control (LRC), disease-free survival (DFS), disease-specific survival (DSS) and overall survival (OS) rates for all patients were 80.2%, 56.4%, 63.7% and 52.2%, respectively. The median TIMP-1 level was 185 ng/mL (range: 22-523 ng/mL) and the mean level (±standard deviation) was 192 (±87) ng/mL. Serum TIMP-1 levels were found to be significantly increased in patients with preoperative CRP>12 mg/L and in those who died from rectal cancer or had cT4 tumours. No correlation was established for age, gender, carcinoembriogenic antigene (CEA) level, platelets count, histopathological grade, response to preoperative therapy, resectability and disease reappearance. On univariate analysis, various parameters favourably influenced one or more survival endpoints: TIMP-1 <170 ng/mL, CRP <12 mg/L, platelets count <290 10E9/L, CEA <3.4mg/L, age <69 years, male gender, early stage disease (cN0 and/or cT2-3), radical surgery (R0) and response to preoperative radiochemotherapy. In multivariate model, LRC was favourably influenced by N-downstage, DFS by lower CRP and N-downstage, DSS by lower CRP and N-downstage and OS by lower TIMP-1 level, lower CRP and N-downstage. Conclusions. Although we did not find any association between pretreatment serum TIMP-1 levels and primary tumour response to preoperative radiochemotherapy in our cohort of patients with rectal cancer, TIMP-1 levels were recognized as an independent prognostic factor for OS in these patients.